Sheldon Adelson, the casino magnate and billionaire financier of Republican candidates and causes,  admitted in an SEC filing submitted Friday that his company probably broke a federal anti-bribery law through its business dealings in China.

In an annual regulatory report by Adelson's Las Vegas Sands Corporation, the company wrote that an internal audit determined it had, “likely violated a federal law against bribing foreign officials." The report did not go into specifics, but said the company was cooperating with investigators who are looking into the matter.

The company is under investigation by the Department of Justice, the Federal Bureau of Investigation and the SEC for their shady business dealings in China. Yet until Friday, the company had given no admission or indication of wrongdoing.

Adelson aggressively moved to tap the emerging Chinese economy over the past decade, striking deals with the government, opening two casinos and pushing other profitable ventures there. While those endeavors made Adelson fabulously wealthy, there was much speculation that those operations were not entirely on the level. Specifically, the company is suspected of bribing officials for sweetheart land deals and donating cash to an organized crime gang to drive business to their casinos.

Adelson became a major player in the last election cycle, most notably for the millions of dollars he dumped on Newt Gingrich's failed presidential bid. He dropped at least $60 million on various campaigns in 2012, making him the single biggest political donor ever.